Discovering
an Electric Violin

by Dan Trueman

It
was my first "concert" with electric violin. I had been
playing electric violin for quite some time, but always in clubs,
with weird rock bands, singing harmonies, using distortion and a big
electric guitar tube amplifier. But this was a "concert,"
in a concert hall with nice acoustics at a conservatory and (mostly)
attentive listeners. So I lugged in my Fender amp, my Alesis
Quadraverb (a digital effects unit), my MIDI foot-pedal and my
flying-V, strap-on 6-string fretted electric violin (made by Mark
Wood), and played. Though I grew up playing chamber music, performing
with orchestras, and doing "concerts" on a regular basis,
it had been many years since I had played in a "concert"
setting, and it felt simultaneously foreign and familiar.

I learned so
much in that concert. Let me start with the details, because that's
where the whole process began for me. I set up the amplifier facing
the audience, and sat down next to it with my foot-pedal. Usually, at
home or in a club, I'm standing facing my amplifier, getting it full
blast in the face. But I had to sit for this (needing both feet for
some complicated foot-pedal maneuvers) and didn't really think facing
the amplifier would be appropriate I'd be blocking the sound
and, regardless of Miles Davis's example, I didn't think I could play
with my back to the audience. So I sat down next to the amp and
played. It was shocking how different it sounded to me than when I
was face to face with the amp. All the high frequencies were gone, so
I began compensating by hitting the high strings hard and the
lightening up on the low strings. I was also puzzled by the sound of
my instrument in the hall. It was clear that people in the central
seats were getting a decent sound from the amp, but as I wandered the
hall with a long cord, I could hear that anyone outside of the
central seating was also missing the high frequencies; what an awful sound!

I also noticed
something subtler, but in some ways even more deeply troubling, and
it wasn't until several years later that I was really able to put my
finger on the difficulty. The acoustic instrumentalists I was playing
with on that concert filled the hall beautifully; it was as if their
instrument and the hall were one, working together symbiotically. My
own instrument, on the other hand, sounded like it was from another
world. Oil and water. I messed with the reverb on my amp, to try to
get it to sound better. I turned the reverb off, but then it sounded
just terrible; dry and ugly, and instead of hearing the warm sound of
the hall, all I could hear was the sound of my instrument bouncing
off the back wall, like an echo. In the end, it was an intractable
problem; oil and water it was, at least for that concert. The only
thing I could think to do was to put mics on the acoustic instruments
and put us all through a PA, so we could be artificially mixed and
essentially bypass the acoustics of the hall, but there wasn't time,
and it just seemed like an unsatisfying non-solution.

Finally, my
solid-body electric violin sounded painfully coarse in the same room
as these fine old acoustic instruments, in spite of my best efforts
to tweak the equalization (I have spent untold hours messing with EQ
and electric violins). These instruments, with their piezo pickups
directly under the strings in the bridges, produce a remarkably clean
signal, one that can be quite effective when processed, but one that
is decidedly bland and even (to my ears) ugly when compared to most
acoustic instruments. And, between my stomping on the foot-pedals to
try to control the effects box and negotiating my fretted, undeniably
phallic strap-on instrument, I felt a bit like a zoo animal.

So I played
the concert (it went ok, though was an unsatisfying musical/sonic
experience for me) and spent the next several months wondering if I
could ever make "concert" music with the electric violin.
Now, I'm well aware of the current trend in concert music to amplify
everything, make it loud, and bypass the natural acoustics of
performance spaces, and I quite enjoy it at times, both as a player
and listener, but I also feel like it shouldn't be the only option
when we are interested in combining old instruments with new
technologies in spaces that have their own beautiful acoustic
properties. I also have a social problem with it; while it is
certainly possible to make things sound good in a hall when you have
a good system and good engineers, and it is even often possible to
arrange for a decent monitoring system for the musicians, it is
undeniably a different social experience for the musicians to make
music in this kind of context. It is so different that not only is
the performer's musical experience deeply impacted, our whole notion
of how we make music and what kind of music we will make is changed.
This is not just a practical matter, this is a musical, aesthetic
matter, and we should have options so we aren't using a PA simply
because that is our only choice.

From my point
of view at the time, there were Three Problems: 1) the tone of my
instrument and EQ; 2) the amplifiers/speakers; 3) the foot-pedal as
controller for signal processing. I don't think I would have made
much progress on any of these fronts if I hadn't had the opportunity
to work with Perry Cook, a computer scientist, engineer, and musician
at Princeton, where I became a graduate student the year after my
formative concert experience. With Perry, I embarked on two separate
projects to address the Three Problems.

For Problem
#1, we decided to study the natural EQ that instrument bodies create
when they filter the sounds of strings being driven through them.
This is, after all, the missing element in a solid-body instrument.
We went about taking what are called "impulse responses"
for a variety of violins, guitars, and mandolins. Here's the idea:
you whack the bridge of the instrument with a very small hammer, and
record the way the body colors that sound (the strings are left on,
but damped). This response then serves as a model for building an
equalization filter that you can then use with an electric violin (or
any other sound, for that matter). Engineers have done this kind of
thing for years, and it is analogous to the way reverbs are built
these days; generate an impulse (via firing a pistol or something
similar) in a concert hall, record the way that impulse is
dissipated, and that becomes your model for building a reverb (or in
the case of some recent reverbs like Altiverb, the response is used
directly to create reverb via a process known as convolution). But
instead of just recording the response with a single mic, we set up
an array of twelve microphones pointing inwards so we could see how
the sound of the instrument varied in space.

An array of
12 microphones, with an instrument inside

So we went
about whacking the bridges of several instruments and collecting sets
of 12 "directional impulse responses" which could be used
to create EQs for my electric violin.

Simultaneous
with this process, I was thinking about Problem #2. Taking it step by
step, I thought things might be improved if I used two speakers: one
for the audience and one for me. This way I could hear the high
frequencies and feel more comfortable with the sound of the
instrument. Of course, it would still sound lousy to the musicians on
stage with me. Ok, then let's try three speakers, adding one for the
other musicians. Well, you need more than three if you have more than
one other musician, so let's keep adding. Finally, it occurred to me
that maybe we could set up an array of speakers pointing outwards,
arranged like a sphere. Without having any idea how this might be
done, I mentioned the idea to Perry and his eyes lit up. A couple
days later he invited me over to his house to see something he had built:

Looking like
something that NASA might build if they could only shop at Home
Depot, the Boulder was the inverse of the microphone array we were
using to collect impulse responses: a set of 12 speakers
pointing outwards.
Now we could take the impulse responses we were collecting, apply
them to my electric violin through these 12 speakers and create a
virtual replica of the acoustic qualities of the instruments we had
abused. Thus our first spherical speaker was born (I should point out
that spherical speakers have been used since the 1950s, though
primarily for acoustic studies, not as musical instruments).

I noticed
something remarkable when I started playing with the Boulder (and the
Bomb, a spherical speaker made out of two metal salad bowls, and
later, R2, a speaker made out of two wooden salad bowls and tom-tom
legs): I didn't need reverb anymore. With the sound of my electric
violin coming out all directions, it was filling the hall more like
acoustic instruments doI was actually engaging the acoustic
qualities of the performance space, and getting the natural reverb
that acoustic musicians are accustomed to (and boy was it fun to
bring it into the bathroom!). This was particularly true when using
the 12 EQs from the impulse responses, but even with a mono signal
going through the speaker I was able to get a full, reverberant
sound. This was a revelation, and I have been using spherical
speakers (or, more recently, hemispherical speakers, which are
excellent as well) ever since.

It is
difficult to overstate the impact these speakers have had on my
subsequent work. After building a few speakers by hand and coming up
with a more refined design (with my father, physicist Larry Trueman),
I began (with my long time collaborate Curtis Bahn) to pursue
manufacturers in the hope of having many of these speakers built. At
RPI, Curtis eventually initiated a project where they built over 50
hemispherical speakers, which in turn spawned a mini-business (see http://www.oddnoise.com/spheres.html)intended to meet the requests of several other artists
interested in using them. Over the years, my electronic improvisation
ensemble interface
(with Curtis and the dancer/shakuhachi player Tomie Hahn) has
performed regularly with them, sometimes using dozens of them at a
time. interface
had always performed with a PA system, and it was remarkable how much
our music changed when we started using the new speakers. The
speakers have a sense of presence
in a space; they are definable, localized sources of sounds, like old
fashioned musical instruments. They also help create a sense of intimacy
rare in electronic music; rather than hurling sound at an audience
from behind the plane
of separation
that PA systems create between an audience and performers, we felt
like we could create delicate sonic spaces that invited listeners to
lean forward, and even enter our space and walk around. With these
speakers, the whole notion of the on-stage monitor becomes
irrelevant; the speakers are instruments, and we simply set the
volume to whatever sounds appropriate. This has noticeable social
ramifications; when we play, it feels more like an old fashioned
chamber music experience than the familiar PA/monitor situation. Our
improvisations began to change, becoming more detailed, with a wider
dynamic range (particularly on the quiet side).

I found all of
this tremendously inspiring, and began to compose chamber pieces that
combined my electric violin and spherical speakers with cellos,
violin, guitars, percussion, etc.... My first electronic chamber
piece, Machine
Language,
was for electric violin (no fancy signal processing or laptop, just
a single spherical speaker for the sound of the e-violin), violin,
cello and percussion. This was followed by a trio, Still,
for violin, cello, and electric violin/laptop (which was premiered
at the ACO's first OrchestraTech festival in 2001) that introduced
noisy electronic textures into the ensemble (using three spherical
speakers, one for the electric violin, two for the electronics, all
placed in and around the ensemble). My next piece,
Counterfeit Curio,
for Pierrot/percussion/electric-violin/laptop, required more
speakers to match the size of the ensemble, so I used four
hemispherical speakers (by now I had decided that hemispheres were
actually more appropriate than spheres, spheres being almost too
reverberant). Emboldened, I entered the most challenging of chamber
music contexts with the piece Traps,
for string quartet and electric violin/laptop; with Traps,
the four hemispherical speakers sit discretely on the floor, one
near each player, and the electronics create a kind of gentle sonic
halo from within the ensemble.

Over the
course of composing these pieces, the speakers went through many
changes, and I also continued to explore different kinds of electric
violins. I eventually abandoned the strap-on flying-V instrument
(though I still have it!) and went through several other designs, all
solid-body. Finally, in the summer of 2002 I commissioned a 6-string
acoustic/electric violin from Eric Aceto. This instrument has a full
resonating body (but no F-holes), and rather than having pickups
directly under the strings, the pickup is on the top of the violin
and gets a spectrally rich sound, colored by the body of the instrument.

Also, having a
full resonant body, the instrument can take the full weight of the
bow arm; one of the ironic things I found with solid-body instruments
is that, in spite of their ability to be very loud, you can't really
sink the bow into themthere is no place for the energy to go,
so the strings just give out. I also found that with the Aceto
instrument, the need for applying equalization to the sound goes
away; the resonating body takes care of that.

So, it is with
this wonderful new Aceto electric violin and eight hemispherical
speakers that I join the ACO on January 21. Traps
Relaxed,
for strings, percussion and electric violin/laptop, is a
re-imagining of my earlier piece for string quartet and electric
violin/laptop. With both Traps
and Traps
Relaxed,
I am exploring a subtle algorithm where the sound of my violin is
cut into tiny pieces (grains), transposed, and scattered across the
speakers within the ensemble. The algorithm attempts to transpose my
sound to a given "trap" pitch (or pitches). So, if the trap
pitch is a high F, and I play an A below that, it will transpose my
sound up a minor sixth:

Sometimes,
however, it will also still remember notes I had played slightly
earlier, so if I played a low D and then returned to the high A, we
might also hear a bit of Bb (the D transposed up a minor sixth):

(note how when
I play the low double stop we can hear a noisy spattering of grains;
these are the algorithm's attempt to transpose that low double-stop
up to the high trap A).

Both Traps
and Traps
Relaxed
go through a series of "traps," exploring their various
harmonic and textural possibilities. Traps
Relaxed
is a bit more expansive than the original Traps,
lingering in places, discovering new possibilities that the larger
ensemble allows.

The electric
"violin" (which includes the Aceto, the speakers, and the
laptop) that I will be using in Traps
Relaxed
is one of the main instruments that I am working with these days, and
I am thrilled to have the opportunity to try with the ACO at Zankel;
each new piece, ensemble and hall that I play these instruments in
brings new revelations. I have never used them with such a large
ensemble (17 instruments); if all goes well I'll try 16 hemispheres
(or more) with a full orchestra!

Some of you
are probably wondering about Problem #3 (the Foot-Pedal as Controller
for Signal Processing Problem). It is beyond the scope of this
article to describe what we've been doing to address this problem,
but I will leave you with what I hope will be an intriguing image:

This is the
Bowed-Sensor-Speaker-Array (BoSSA), an instrument I built that takes
its inspiration from the violin. It consists of: a spherical speaker;
a violin bow with sensors that detect bow position, speed, pressure;
an ebony fingerboard with sensors that detect finger position; and a
set of sensors arranged like a "bridge" that can be bowed.
The data from these sensors are used to control synthesis and signal
processing algorithms on a laptop, which in turn sends sound out the
twelve elements of the spherical speaker. It sort of feels like a
cello to play, with the speaker sitting in my lap. Sort of.... If you
are intrigued, check out a video of BoSSA here
and visit the BoSSA
website.BoSSA
is also the inspiration for PLOrk (the Princeton Laptop
Orchestra), a new ensemble being formed at Princeton that combines a
dozen hemispherical speakers with a variety of sensor/control
devices; stay tuned!